]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commitdiff
sched/fair: Test list head instead of list entry in throttle_cfs_rq()
authorCong Wang <xiyou.wangcong@gmail.com>
Wed, 24 Jun 2015 19:41:47 +0000 (12:41 -0700)
committerIngo Molnar <mingo@kernel.org>
Mon, 6 Jul 2015 12:15:08 +0000 (14:15 +0200)
According to the comments, we need to test if this is
the first throttled task, however, list_empty() tests on
the entry cfs_rq->throttled_list, not the head, this is wrong.

This is a bug because we don't re-init the list entry after
removing it from the list, so list_empty() could return false
even if the list is really empty.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1435174907-432-1-git-send-email-xiyou.wangcong@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/sched/fair.c

index 65c8f3ebdc3c5d58d148780c84c90fe54dc6e4dc..d113c3ba8bc44b4f50a12e9c055cb70b63a632fc 100644 (file)
@@ -3683,7 +3683,7 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq)
        cfs_rq->throttled = 1;
        cfs_rq->throttled_clock = rq_clock(rq);
        raw_spin_lock(&cfs_b->lock);
-       empty = list_empty(&cfs_rq->throttled_list);
+       empty = list_empty(&cfs_b->throttled_cfs_rq);
 
        /*
         * Add to the _head_ of the list, so that an already-started